Piston structure

Abstract

The utility model discloses a piston structure which comprises a piston body, the top of the piston body is provided with a combustion chamber, one end of the combustion chamber is open, the combustion chamber is of a rotary body structure, a plurality of step faces which are distributed in a step mode in the axial direction of the piston body are formed in the combustion chamber, and the step faces are sequentially connected in the radial direction of the piston body. Therefore, according to the piston structure, the multiple step faces which are distributed in the axial direction of the piston body in the stepped mode and sequentially connected in the radial direction of the piston body are arranged in the combustion chamber, gas turbulence can be further enhanced, and therefore mixing and diffusion of oil beams and air in the combustion chamber are further promoted; and the stepped surface is beneficial to rapid separation of the oil beam from the wall surface after the oil beam impacts the inner wall of the combustion chamber, so that substandard emission of an engine caused by fuel accumulation on the wall surface can be avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of pistons, in particular to a piston structure. Background Art

[0002] With the development of society and the continuous enhancement of people's environmental awareness, automobile engines are gradually developing towards high efficiency, energy saving and emission reduction. Among them, there are many factors that affect emissions. The piston, as a key component of the motion system, has a vital impact on the combustion and emissions of the engine. The combustion chamber on the top of the piston, as the place where oil and gas are mixed and burned, has a great impact on the combustion and emissions of the engine.

[0003] In the related technology, the pistons commonly used at present are usually traditional straight-mouth or tapered ω-type combustion chambers. Both types of combustion chambers have the advantages of low fuel consumption and easy starting. However, the former can only meet the emission standards of stages I, II, and III, and the elimination of straight-mouth combustion chambers is an inevitable trend. The ω-shaped tapering of the latter can enhance gas turbulence and promote the diffusion, mixing and combustion of oil and gas. However, the tapered ω-type combustion chamber is prone to wet walls, and the oil and gas mixing is not uniform, making it difficult to meet current engine emission requirements. Utility Model Content

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a piston structure that, by providing a plurality of stepped surfaces in the combustion chamber, distributed in a stepped manner along the axial direction of the piston body and sequentially connected along the radial direction of the piston body, further enhances gas turbulence, thereby further promoting the mixing and diffusion of the oil beam and air in the combustion chamber. Furthermore, the stepped surfaces facilitate rapid separation of the oil beam from the combustion chamber inner wall after impacting the wall, thereby preventing substandard engine emissions due to fuel accumulation on the wall.

[0005] To achieve the above-mentioned purpose, the present invention provides a piston structure, comprising:

[0006] The piston body has a combustion chamber on the top of the piston body which is open at one end and is constructed as a rotating body structure. A plurality of step surfaces are formed in the combustion chamber and are distributed in a stepped manner along the axial direction of the piston body, and the plurality of step surfaces are connected in sequence along the radial direction of the piston body.

[0007] According to the piston structure of the embodiment of the present invention, the piston structure can further enhance gas turbulence by arranging a plurality of step surfaces in the combustion chamber that are distributed in a stepped manner along the axial direction of the piston body and are sequentially connected along the radial direction of the piston body, thereby further promoting the mixing and diffusion of the oil beam and the air in the combustion chamber. At the same time, the step surfaces help the oil beam to quickly separate from the wall after hitting the inner wall of the combustion chamber, thereby avoiding substandard engine emissions due to fuel accumulation on the wall.

[0008] According to one embodiment of the present invention, the multiple step surfaces include: a first step surface, a second step surface and a third step surface, the first step surface, the second step surface and the third step surface are connected in sequence, the distances between the first step surface, the second step surface and the third step surface and the top surface of the piston body increase in sequence, and the first step surface is also suitable for being connected to the top surface of the piston body through the first connecting surface in the combustion chamber.

[0009] According to one embodiment of the present invention, along the radial direction of the piston body, the first step surface is an arcuate surface, and the maximum diameter of the first step surface relative to the rotation center of the combustion chamber is A, satisfying the relationship: 61mm≤A≤61.2mm.

[0010] According to one embodiment of the present invention, the second step surface is an arcuate surface. Along the radial direction of the piston body, the maximum diameter of the second step surface relative to the rotation center of the combustion chamber is B, satisfying the relationship: 58mm≤B≤58.2mm;

[0011] The second step surface further includes a first inclined surface. The inclined angle of the second step surface is α, which satisfies the relationship: 160°≤α≤165°.

[0012] According to one embodiment of the present invention, the third stepped surface is configured as a first circular surface, the radius of the first circular surface is r2, and the relationship is satisfied: 5mm≤r2≤5.5mm;

[0013] Along the axial direction of the piston body, the maximum distance between the third step surface and the top surface of the piston body is H1, satisfying the relationship: 12.8mm≤H1≤13mm;

[0014] Along the radial direction of the piston body, the maximum diameter of the third step surface relative to the rotation center of the combustion chamber is C, which satisfies the relationship: 37.8mm≤C≤38.2mm.

[0015] According to an embodiment of the present invention, a first transition fillet r3 is provided between the second step surface and the third step surface, satisfying the relationship: 1.5 mm ≤ r3 ≤ 2 mm.

[0016] According to one embodiment of the present invention, the first transition fillet protrudes toward the center of rotation of the combustion chamber. The first transition fillet is arranged around the center of rotation of the combustion chamber and forms a throat of the combustion chamber. Along the radial direction of the piston body, the diameter of the throat relative to the center of rotation of the combustion chamber is D, satisfying the relationship: 36.5mm≤D≤36.7mm.

[0017] According to one embodiment of the present invention, a protruding structure is formed on the bottom wall of the piston body, and the minimum distance between the protruding structure and the top surface of the piston body is H3, satisfying the relationship: 3.3mm≤H3≤3.5mm.

[0018] According to one embodiment of the present invention, at least a portion of the top of the raised structure is configured as a second circular surface, the radius of the second circular surface is r1, and the relationship is satisfied: 5.5 mm ≤ r1 ≤ 6 mm.

[0019] According to an embodiment of the present invention, the side wall of the protruding structure is configured as a second inclined surface, and the inclined angle of the side wall of the protruding structure is β, which satisfies the relationship: 77.5°≤β≤80.5°.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of a piston structure according to one embodiment of the present invention;

[0022] Figure 2 It is a partial schematic diagram of a piston structure according to an embodiment of the present utility model.

[0023] Reference numerals:

[0024] Piston structure 100;

[0025] Piston body 1; combustion chamber 11; first step surface 12; second step surface 13; third step surface 14; throat 15; protrusion structure 16; internal cooling oil channel 17; first connecting surface 18. DETAILED DESCRIPTION

[0026] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] The piston structure 100 proposed in an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0028] like Figure 1-Figure 2 As shown, the piston structure 100 according to an embodiment of the present invention includes: a piston body 1, a combustion chamber 11 with one end open and constructed as a rotating body structure is provided on the top of the piston body 1, and a plurality of step surfaces are formed in the combustion chamber 11 and are distributed in a stepped manner along the axial direction of the piston body 1, and the plurality of step surfaces are connected in sequence along the radial direction of the piston body 1.

[0029] Specifically, the engine includes a cylinder and a cylinder head, which are assembled together to form a closed combustion space. The piston structure 100 is arranged in the combustion space, and the piston structure 100 can move up and down in the combustion space. Furthermore, the piston structure 100 includes a piston body 1, and the top of the piston body 1 is provided with a combustion chamber 11 with one end open and constructed as a rotating body structure. The combustion chamber 11 of the piston body 1 is arranged opposite to the cylinder head. When the piston body 1 moves toward the cylinder head, the piston body 1 compresses and performs work.

[0030] Furthermore, a plurality of stepped surfaces are formed in the combustion chamber 11, such as Figure 1 As shown, multiple step surfaces are distributed in a stepped manner along the axial direction (up and down direction) of the piston body 1, and are connected in sequence along the radial direction of the piston body 1. For example, the number of step surfaces can be 2, 3, 4, or 5, and is set according to actual needs. It can be understood that since the combustion chamber 11 is a rotating body structure, each step surface can be approximately regarded as an annular surface. When the oil beam enters the combustion chamber 11, the oil beam contacts the step surface, and the step surface can promote the diversion of the oil beam, so that part of the oil beam is diverted to flow to a deeper area of ​​the combustion chamber 11, and the other part of the oil beam is turned back in a direction away from the step surface. In this way, the setting of the step surface is conducive to improving the mixing and diffusion of the oil beam and the air, and further enhancing the gas turbulence in the combustion chamber 11. The turning back of part of the oil beam also helps the oil beam to quickly separate from the wall after hitting the inner wall of the combustion chamber 11, thereby reducing the risk of fuel accumulation on the wall, and reducing HC and carbon soot emissions caused by fuel accumulation on the wall, so that the engine can meet the emission standards of existing regulations.

[0031] According to the piston structure 100 of the embodiment of the present invention, the piston structure 100 can further enhance gas turbulence by arranging a plurality of step surfaces in the combustion chamber 11 that are distributed in a stepped manner along the axial direction of the piston body 1 and are sequentially connected along the radial direction of the piston body 1, thereby further promoting the mixing and diffusion of the oil beam and the air in the combustion chamber 11. At the same time, the step surfaces help the oil beam to quickly separate from the wall after hitting the inner wall of the combustion chamber 11, thereby avoiding substandard engine emissions due to fuel accumulation on the wall.

[0032] In some embodiments of the present invention, Figure 1As shown, the multiple step surfaces include: a first step surface 12, a second step surface 13 and a third step surface 14, which are connected in sequence. The distances between the first step surface 12, the second step surface 13 and the third step surface 14 and the top surface of the piston body 1 increase in sequence, and the first step surface 12 is also suitable for being connected to the top surface of the piston body 1 through a first connecting surface 18 in the combustion chamber 11. There is a second transition fillet r5 between the first step surface 12 and the first connecting surface 18, which satisfies the relationship: 0.5mm≤r5≤1mm, and there is a third transition fillet r4 between the first step surface 12 and the second step surface 13, which satisfies the relationship: 1mm≤r4≤1.5mm.

[0033] Specifically, the piston structure 100 is Figure 1 Taking the placement direction shown as an example, two groups of first step surfaces 12, second step surfaces 13, and third step surfaces 14 symmetrically along the rotation center of the combustion chamber 11 are formed in the combustion chamber 11, wherein each group of first step surfaces 12, second step surfaces 13, and third step surfaces 14 are sequentially spaced and arranged in steps from top to bottom, and each group of first step surfaces 12, second step surfaces 13, and third step surfaces 14 are sequentially connected along the radial direction of the piston body 1, and the first step surface 12 is also connected to the top surface of the piston body 1 through the first connecting surface 18 in the combustion chamber 11. The first step surface 12, the second step surface 13, and the third step surface 14 can be constructed as horizontal planes, inclined planes, or curved surfaces, and the specific selection is based on actual conditions to ensure that the first step The stepped surface 12, the second stepped surface 13 and the third stepped surface 14 are arranged relative to each other in a position facing the cylinder head. In this way, after the oil beam enters the combustion chamber 11, the oil beam contacts the first stepped surface 12, the second stepped surface 13 and the third stepped surface 14 in sequence. The first stepped surface 12 and the second stepped surface 13 allow a part of the oil beam to be diverted to flow to a deeper area (the third stepped surface 14) of the combustion chamber 11, and the other part of the oil beam is turned back in a direction away from the stepped surface, which is beneficial to improve the mixing and diffusion of the oil beam and the air and enhance the gas turbulence in the combustion chamber 11. The turning back of the oil beam also helps the oil beam to quickly separate from the wall after hitting the inner wall of the combustion chamber 11, thereby reducing the risk of fuel accumulation on the wall, so that the engine can meet the emission standards of existing regulations.

[0034] In some embodiments of the present invention, Figure 2 As shown, along the radial direction of the piston body 1, the first step surface is an arcuate surface, and the maximum diameter of the first step surface 12 relative to the rotation center of the combustion chamber 11 is A, which satisfies the relationship: 61mm≤A≤61.2mm. Specifically, the first step surface 12 can be constructed as an arcuate surface, such as Figure 1 and Figure 2As shown, the first step surface 12 and the first connecting surface 18 of the piston body 1 jointly form a sub-combustion area, which is cylindrical. The sub-combustion area has a maximum diameter A relative to the rotation center of the combustion chamber 11, and satisfies the relationship: 61mm≤A≤61.2mm, that is, the maximum diameter of the sub-combustion area can be 61mm, 61.1mm, 61.2mm, etc. Compared with the traditional straight-mouth or tapered ω-type combustion chamber 11, the width of the combustion chamber 11 in the radial direction is greatly improved. In this way, compared with the traditional diesel engine tapered ω-type combustion chamber 11, the high-temperature position of the combustion chamber 11 of the piston body 1 in this application can be closer to the internal cooling oil channel 17, thereby improving the durability of the piston structure 100.

[0035] In some embodiments of the present invention, Figure 2 As shown, the second step surface 13 is an arcuate surface. Along the radial direction of the piston body 1, the maximum diameter of the second step surface 13 relative to the rotation center of the combustion chamber 11 is B, which satisfies the relationship: 58mm≤B≤58.2mm. Since the combustion chamber 11 is a rotating body structure, the second step surface 13 can be approximately regarded as an arcuate surface. Along the radial direction of the piston body 1, the maximum diameter of the second step surface 13 relative to the rotation center of the combustion chamber 11 is B, which satisfies the relationship: 58mm≤B≤58.2mm. In other words, the maximum diameter of the second step surface 13 relative to the rotation center of the combustion chamber 11 can be 58mm, 58.1mm, 58.2mm, etc., that is, the maximum diameter of the second step surface 13 is smaller than the maximum diameter of the first step surface 12. This is beneficial to further improve the gas turbulence at the second step surface 13 and reduce the risk of fuel accumulation on the wall of the second step surface 13.

[0036] Furthermore, the second step surface further includes a first inclined surface, and the inclined angle of the second step surface is α, which satisfies the relationship: 160°≤α≤165°. Specifically, Figure 2 As shown, the first inclined surface gradually tilts downward as it moves away from the top surface of the piston body 1. The highest point of the first inclined surface is H4 away from the top surface of the piston body 1, satisfying the relationship: 2.5mm≤H4≤2.8mm. The lowest point of the first inclined surface is H2 away from the top surface of the piston body 1, satisfying the relationship: 5.2mm≤H2≤5.5mm. Furthermore, the inclination angle of the second step surface 13 is α, satisfying the relationship: 160°≤α≤165°. That is to say, the inclination angle of the second step surface 13 can be 160°, 162°, 163°, etc.

[0037] In some embodiments of the present invention, Figure 2As shown, the third step surface 14 is constructed as a first circular surface, the radius of the first circular surface is r2, and the relationship: 5mm≤r2≤5.5mm; along the axial direction of the piston body 1, the maximum distance between the third step surface 14 and the top surface of the piston body 1 is H1, which satisfies the relationship: 12.8mm≤H1≤13mm; along the radial direction of the piston body 1, the maximum diameter of the third step surface 14 relative to the rotation center of the combustion chamber 11 is C, which satisfies the relationship: 37.8mm≤C≤38.2mm.

[0038] Specifically, the third step surface 14 is constructed as a first circular surface, and the radius of the first circular surface can be 5mm, 5.1mm, 5.5mm, etc., which is conducive to improving the gas turbulence at the third step surface 14. Furthermore, along the axial direction of the piston body 1, the maximum distance between the third step surface 14 and the top surface of the piston body 1 is H1, satisfying the relationship: 12.8mm≤H1≤13mm, that is, the distance from the lowest point of the third step surface 14 to the top surface of the piston body 1 can be 12.8mm, 12.9mm, 13mm, etc., so that the piston structure 100 of the present application can effectively reduce the overall height and friction area of ​​the piston, and the friction area is reduced by about 17.5%, thereby resulting in a reduction in friction loss by 0.5%, and the reduction in the overall height of the piston is conducive to reducing weight, thereby improving the economy of the engine, and the reduction in the overall height and weight of the piston can effectively reduce fuel consumption by about 0.3%, and the reduction in weight can reduce the second-order reciprocating inertia force of the engine, which is conducive to reducing noise. At the same time, the coordinated use of the first step surface 12, the second step surface 13, and the third step surface 14 can locate the high-temperature combustion zone in the rich area of ​​the combustion chamber 11 rather than directly facing the bottom surface of the cylinder head, thereby effectively reducing the temperature of the bottom surface of the cylinder head and reducing the risk of cracking of the cylinder head due to high temperature.

[0039] In some embodiments of the present invention, Figure 2 As shown, a first transition radius r3 is defined between the second step surface 13 and the third step surface 14, satisfying the relationship: 1.5mm≤r3≤2mm. In other words, the second step surface 13 and the third step surface 14 are connected by the first transition radius, which can be 1.5mm, 1.8mm, 2mm, or other angles, depending on actual needs. This first transition radius creates a smoother transition between the second step surface 13 and the third step surface 14, helping to prevent the risk of fuel accumulation on the wall.

[0040] In some embodiments of the present invention, Figure 2As shown, the first transition fillet protrudes toward the rotation center of the combustion chamber 11. The first transition fillet is arranged around the rotation center of the combustion chamber 11 and forms the throat 15 of the combustion chamber 11. Along the radial direction of the piston body 1, the diameter of the throat 15 relative to the rotation center of the combustion chamber 11 is D, satisfying the relationship: 36.5mm≤D≤36.7mm. That is to say, the first transition fillet protrudes toward the center of rotation of the combustion chamber 11 and is arranged around the center of rotation of the combustion chamber 11, so that a tight throat 15 is formed between the second step surface 13 and the third step surface 14. Along the radial direction of the piston body 1, the diameter of the throat 15 relative to the center of rotation of the combustion chamber 11 is D, satisfying the relationship: 36.5mm≤D≤36.7mm. For example, the diameter of the throat 15 relative to the center of rotation of the combustion chamber 11 can be 36.5mm, 36.6mm, or 36.7mm, and can be set according to actual needs. In this way, the gas turbulence at the throat 15 can be increased, which is beneficial to improving the mixing and diffusion of the oil beam and air at the throat 15.

[0041] In some embodiments of the present invention, Figure 2 As shown, the bottom wall of the piston body 1 is formed with a raised structure 16. The minimum distance between the raised structure 16 and the top surface of the piston body 1 is H3, satisfying the relationship: 3.3mm≤H3≤3.5mm. In other words, an upward raised structure 16 can be provided on the bottom wall of the piston body 1. The minimum distance between the raised structure 16 and the top surface of the piston body 1 is H3, satisfying the relationship: 3.3mm≤H3≤3.5mm. For example, the minimum distance between the raised structure 16 and the top surface of the piston body 1 can be 3.3mm, 3.4mm, or 3.5mm. In this way, by providing the raised structure 16, the gas turbulence in the combustion chamber 11 can be further enhanced, thereby further improving the mixing and diffusion of the oil beam and air, which is beneficial to improving the engine combustion efficiency.

[0042] In some embodiments of the present invention, Figure 2 As shown, at least a portion of the top of the raised structure 16 is configured as a second circular surface, and the radius of the second circular surface is r1, satisfying the relationship: 5.5mm≤r1≤6mm. In other words, at least a portion of the top of the raised structure 16 is configured as a second circular surface, and the radius of the second circular surface can be 5.5mm, 5.6mm, or 6mm. This reduces the risk of fuel accumulation on the top of the raised structure 16, allowing the engine to meet existing regulatory emission standards.

[0043] In some embodiments of the present invention, Figure 2As shown, the sidewall of the protrusion 16 is configured as a second inclined surface, and the angle of inclination of the sidewall of the protrusion 16 is β, which satisfies the relationship: 77.5°≤β≤80.5°. In other words, when the sidewall of the protrusion 16 is configured as a second inclined surface, the protrusion 16 as a whole has a frustum structure. The angle of inclination of the sidewall of the protrusion 16 can be 77.5°, 79.5°, 80.5°, etc., thereby reducing the risk of fuel accumulation on the sidewall of the protrusion 16, allowing the engine to meet existing regulatory emission standards.

[0044] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0045] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0046] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative use of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0047] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A piston structure, characterized in that: include: A piston body (1), wherein a combustion chamber (11) having one end open and constructed as a rotating body is provided on the top of the piston body (1), wherein a plurality of stepped surfaces distributed in a stepped manner along the axial direction of the piston body (1) are formed in the combustion chamber (11), and the plurality of stepped surfaces are sequentially connected along the radial direction of the piston body (1); The first stepped surface (12) and the first connecting surface (18) of the piston body (1) jointly form a sub-combustion area, and the sub-combustion area is cylindrical; The bottom wall of the piston body (1) is formed with a protruding structure (16), the side wall of the protruding structure (16) is configured as a second inclined surface, and the minimum distance between the protruding structure (16) and the top surface of the piston body (1) is H3, satisfying the relationship: 3.3mm≤H3≤3.5mm.

2. The piston structure according to claim 1, characterized in that: The plurality of step surfaces include: a first step surface (12), a second step surface (13) and a third step surface (14); the first step surface (12), the second step surface (13) and the third step surface (14) are connected in sequence; the distances between the first step surface (12), the second step surface (13) and the third step surface (14) and the top surface of the piston body (1) increase in sequence; and the first step surface (12) is further adapted to be connected to the top surface of the piston body (1) via a first connecting surface (18) in the combustion chamber (11).

3. The piston structure according to claim 2, characterized in that: Along the radial direction of the piston body (1), the first step surface (12) is an arcuate surface, and the maximum diameter of the first step surface (12) relative to the rotation center of the combustion chamber (11) is A, satisfying the relationship: 61mm≤A≤61.2mm.

4. The piston structure according to claim 3, characterized in that: The second step surface (13) is an arcuate surface. Along the radial direction of the piston body (1), the maximum diameter of the second step surface (13) relative to the rotation center of the combustion chamber (11) is B, satisfying the relationship: 58mm≤B≤58.2mm; The second step surface (13) further includes a first inclined surface, and the inclined angle of the second step surface (13) is α, which satisfies the relationship: 160°≤α≤165°.

5. The piston structure according to claim 3, characterized in that: The third stepped surface (14) is constructed as a first circular surface, the radius of the first circular surface is r2, and satisfies the relationship: 5mm≤r2≤5.5mm; Along the axial direction of the piston body (1), the maximum distance between the third step surface (14) and the top surface of the piston body (1) is H1, satisfying the relationship: 12.8 mm ≤ H1 ≤ 13 mm; Along the radial direction of the piston body (1), the maximum diameter of the third step surface (14) relative to the rotation center of the combustion chamber (11) is C, satisfying the relationship: 37.8mm≤C≤38.2mm.

6. The piston structure according to claim 2, characterized in that: There is a first transition fillet r3 between the second step surface (13) and the third step surface (14), which satisfies the relationship: 1.5mm≤r3≤2mm.

7. The piston structure according to claim 6, characterized in that: The first transition fillet protrudes toward the rotation center of the combustion chamber (11), and the first transition fillet is arranged around the rotation center of the combustion chamber (11) and forms a throat (15) of the combustion chamber (11). Along the radial direction of the piston body (1), the diameter of the throat (15) relative to the rotation center of the combustion chamber (11) is D, satisfying the relationship: 36.5mm≤D≤36.7mm.

8. The piston structure according to claim 1, characterized in that: At least a portion of the top of the protruding structure (16) is constructed as a second circular surface, the radius of the second circular surface is r1, and the relationship is satisfied: 5.5 mm ≤ r1 ≤ 6 mm.

9. The piston structure according to claim 1, characterized in that: The inclined angle of the side wall of the protruding structure (16) is β, which satisfies the relationship: 77.5°≤β≤80.5°.

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